JP7112492B2 - Ultrasonic imaging device, ultrasonic imaging system, ultrasonic imaging method and ultrasonic imaging program - Google Patents

Description

The present invention relates to an ultrasonic imaging apparatus, an ultrasonic imaging system, an ultrasonic imaging method, and an ultrasonic imaging program for imaging the inside of a subject using ultrasonic waves.

For example, in health checkups for metabolic syndrome, a CT (Computed Tomography) device or an MRI (Magnetic Resonance Imaging) device is often used to acquire a tomographic image of the abdomen. These devices are large-scale and expensive, and there is also the problem of exposure to radiation. Therefore, in recent years, techniques for acquiring tomographic images using ultrasound have been developed. For example, in Patent Document 1, a plurality of ultrasonic images obtained by intermittently transmitting ultrasonic waves from the probe while moving the probe along the surface of the subject are synthesized to form a synthesized image (panoramic image). A technique for generating an image) is disclosed. With this technique, a composite image showing a cross-section of the abdomen can be obtained only by the subject moving the probe while it is in contact with the abdomen.

Patent No. 5935344

For example, when acquiring a tomographic image of the abdomen, the probe is applied to the vicinity of the flank first, and then moved to the vicinity of the flank on the opposite side via the navel. At this time, in the current composite image, as shown in FIG. 20, the vicinity of the flank corresponding to the initial position of the probe faces upward. In such a composite image, since the umbilicus is not facing upward, there is a problem that it is difficult for the subject or the like to grasp the state of the abdomen.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ultrasonic imaging apparatus capable of displaying an ultrasonic composite image that allows a subject to easily grasp the state of the subject. .

An ultrasonic imaging apparatus according to the present invention receives ultrasonic waves transmitted from a plurality of mutually different positions on the surface of a subject toward the inside of the subject and reflected inside the subject, and corresponds to each of the positions. an ultrasonic image generator for generating each of the ultrasonic images, an image synthesizing unit for synthesizing the ultrasonic images at each position to generate a composite image of the cross section of the subject, and adjusting the angle of the composite image, and a direction adjusting unit that orients the specific part included in the synthesized image in a predetermined direction.

An ultrasonic imaging system according to the present invention transmits ultrasonic waves from a plurality of mutually different positions on the surface of the subject toward the inside of the subject, and receives the ultrasonic waves reflected inside the subject. and an ultrasonic imaging apparatus according to the present invention.

An ultrasonic imaging method according to the present invention receives ultrasonic waves transmitted from a plurality of mutually different positions on the surface of a subject toward the inside of the subject and reflected inside the subject, and corresponds to each of the positions. an ultrasonic image generating step of generating each of the ultrasonic images obtained from the above; an image synthesizing step of synthesizing the ultrasound images at the respective positions to generate a synthetic image of the cross section of the subject; adjusting the angle of the synthetic image; and a direction adjusting step of orienting the specific part included in the synthesized image in a predetermined direction.

An ultrasonic imaging program according to the present invention receives ultrasonic waves transmitted toward the interior of the subject from a plurality of positions different from each other on the surface of the subject and reflected inside the subject, and corresponds to each position an ultrasonic image generator for generating each of the ultrasonic images, an image synthesizing unit for synthesizing the ultrasound images at each position to generate a composite image of the cross section of the subject, and adjusting the angle of the composite image, A computer is operated as a direction adjusting unit that orients a specific portion included in the composite image in a predetermined direction.

Advantageous Effects of Invention According to the present invention, it is possible to display an ultrasonic composite image that allows a subject or the like to easily grasp the state of the subject.

1 is a schematic diagram showing the configuration of an ultrasound imaging system according to a first embodiment; FIG. 1 is a block diagram showing the configuration of an ultrasonic imaging apparatus according to a first embodiment; FIG. It is an example of the synthesized image of an abdominal cross section. 4 is a functional block diagram of a direction adjusting section; FIG. It is an example of a composite image in which a region is set. FIG. 4 is an explanatory diagram of a trajectory of a probe and a transmission direction of ultrasonic waves; 7 is a graph showing an example of the relationship between the number of ultrasound images corresponding to a region and the correlation value; It is an example of a composite image in which a region is set approximately in the middle of the rectus abdominis muscle. It is an example of a composite image whose orientation has been adjusted. FIG. 11 is a diagram for explaining another setting example of areas; 4 is a flow chart showing a processing procedure of an ultrasonic imaging method according to the first embodiment; 4 is a flow chart showing a detailed processing procedure of a direction adjustment step in the first embodiment; 2 is a block diagram showing the configuration of an ultrasonic imaging apparatus according to a second embodiment; FIG. FIG. 8 is a functional block diagram of a direction adjusting section in the second embodiment; It is an example of a synthetic image to be adjusted. 1 is an example of a rotated composite image; FIG. 4 is a diagram for explaining matching between a composite image and a template image; 9 is a flow chart showing a processing procedure of an ultrasonic imaging method according to the second embodiment; 9 is a flowchart showing detailed processing procedures of a direction adjustment step in the second embodiment; It is an example of a composite image whose orientation has not been adjusted.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following description and drawings, the same reference numerals denote the same or similar components, and redundant description of the same or similar components will be omitted.

(overall structure)
FIG. 1 is a schematic diagram showing the configuration of an ultrasonic imaging system 1 according to the first embodiment. An ultrasound imaging system 1 includes a probe 2 and an ultrasound imaging device 3 .

The probe 2 is a device that transmits ultrasonic waves from a plurality of mutually different positions on the surface of the subject 9 toward the inside of the subject 9 and receives the ultrasonic waves reflected inside the subject 9. In the embodiment, it is configured so that it can be held and moved by the subject. The lower end of the probe 2 is provided with an ultrasonic transmission/reception surface on which a plurality of ultrasonic transducers are arranged in a row. When acquiring a tomographic image (or a cross-sectional image) of the subject 9, the subject brings the ultrasonic wave transmitting/receiving surface of the probe 2 into contact with the subject 9 and moves the probe 2 along the surface of the subject 9. (scanning with probe 2). During this time, the probe 2 intermittently transmits ultrasonic waves from the ultrasonic wave transmitting/receiving surface toward the inside of the subject 9, and receives ultrasonic waves reflected inside the subject 9 at the ultrasonic wave transmitting/receiving surface. As a result, the probe 2 outputs an electrical signal (echo signal) representing the received ultrasonic waves.

The probe 2 operates in a linear scan mode for acquiring a linear scan image, but may operate in a sector scan mode for acquiring a sector scan image, or may operate in both the linear scan mode and the sector scan mode. It may be possible, or it may be operable in other modes or in combination with other modes. Moreover, in the present embodiment, the subject 9 is mainly the abdomen, but the body part included in the subject 9 is not particularly limited.

The ultrasonic imaging device 3 is connected to the probe 2 by wireless such as WiFi (registered trademark). In this embodiment, the ultrasonic imaging device 3 is configured by, for example, a tablet terminal, generates a plurality of ultrasonic images based on the echo signals received from the probe 2, and further combines these ultrasonic images. It has the function of displaying images.

Note that the ultrasonic imaging device 3 is not particularly limited as long as it can display an image, and can be configured with a general-purpose personal computer, a smart phone, or the like. Also, the method of connecting the probe 2 and the ultrasonic imaging apparatus 3 is not particularly limited, and a wired connection may be used.

(Functions of Ultrasound Imaging Device)
FIG. 2 is a block diagram showing the configuration of the ultrasonic imaging apparatus 3. As shown in FIG. The ultrasound imaging apparatus 3 has a hardware configuration including a display 31, an input device 32, an auxiliary storage device 33, a communication interface section (I/F section) 34, and a display interface section (I/F section) 36. and

The display 31 can be composed of, for example, a liquid crystal display, a plasma display, an organic EL display, or the like. Note that the display 31 may be configured as a device separate from the ultrasonic imaging device 3 .

The input device 32 is a touch panel provided on the surface of the display 31 . The subject can perform an input operation on the image displayed on the display 31 via the input device 32 .

The auxiliary storage device 33 is a non-volatile storage device that stores an operating system (OS), various control programs, and data generated by the programs. Drive), etc. An ultrasonic imaging program P is stored in the auxiliary storage device 33 . The ultrasonic imaging program P may be installed in the ultrasonic imaging apparatus 3 via a network such as the Internet. Alternatively, the ultrasonic imaging program P can be transferred to the ultrasonic imaging apparatus 3 by causing the ultrasonic imaging apparatus 3 to read a computer-readable non-temporary tangible recording medium such as an SD card in which the ultrasonic imaging program P is recorded. can be installed on

The communication interface unit 34 transmits and receives data to and from an external device, and in this embodiment, demodulates a signal received from the probe 2, modulates a control signal to be transmitted to the probe 2, and the like.

The display interface unit 36 displays various image data generated by the arithmetic processing of the ultrasonic imaging apparatus 3 on the display 31 by developing the image data in the VRAM. The combined image and the like thus obtained are displayed on the display 31 .

Although not shown, the ultrasonic imaging apparatus 3 includes, as other hardware configurations, a processor such as a CPU that performs data processing, and a memory (main storage device) that the processor uses as a work area for data processing. I have more.

The ultrasonic imaging apparatus 3 also includes a signal processing unit 35 as a software configuration. The signal processing unit 35 is a functional block realized by the processor executing the ultrasonic imaging program P, and processes echo signals received from the probe 2 to generate an ultrasonic composite image of the subject 9. It has a function of displaying on the display 31 so that an examiner, a doctor, a person engaged in imaging, and the like can easily grasp the state of the subject 9 . In order to realize this function, the signal processing section 35 includes an ultrasonic image generating section 351 , an image synthesizing section 352 and a direction adjusting section 353 . Note that the signal processing unit 35 may be implemented in hardware by a logic circuit formed on an integrated circuit.

The ultrasonic image generator 351 generates an ultrasonic image of the interior of the subject 9 from the echo signal received from the probe 2 . While moving on the surface of the subject 9 , the probe 2 performs ultrasound toward the inside of the subject 9 from a plurality of mutually different positions on the surface of the subject 9 in accordance with control signals transmitted from the ultrasonic imaging device 3 . It transmits sound waves, receives ultrasonic waves reflected inside the object 9 , and outputs echo signals to the ultrasonic imaging device 3 . As a result, each time the probe 2 receives ultrasonic waves, an echo signal is input to the ultrasonic image generation unit 351, and the ultrasonic image generation unit 351 generates a plurality of different images on the surface of the subject 9 from the echo signals. Generating an ultrasound image corresponding to the position. The number of ultrasonic images to be generated varies depending on the transmission/reception time of ultrasonic waves by the probe 2 and the transmission/reception cycle. In this embodiment, n ultrasonic images are generated.

Note that the function of the ultrasonic image generation unit 351 may be provided in a control device that controls the probe 2 . In that case, the control device may be connected to the ultrasonic imaging device 3, or an ultrasonic image may be stored in the control device and transmitted to the ultrasonic imaging device 3 via a recording medium. good.

The image synthesizing unit 352 is a functional block that synthesizes the ultrasound images at the respective positions on the surface of the subject 9 generated by the ultrasound image generating unit 351 to generate a composite image of the cross section of the subject 9. . A well-known technique can be applied to synthesize ultrasound images, and in this embodiment, ultrasound images are synthesized using, for example, feature point matching between ultrasound images. In the present embodiment, the term “cross section” is a concept that includes not only a round cross section but also a partial cross section.

となる。すなわち、１番目の超音波画像上の特徴点（ｘ、ｙ）が、２番目の超音波画像上の特徴点（ｘ'、ｙ'）に移動するとき、

の関係が成り立つ。なお、特徴点の座標には誤差が含まれており、また、ノイズの影響により決定された対応関係自体に誤りが含まれているため、計算に悪影響を及ぼす外れ値をＲＡＮＳＡＣアルゴリズムにより除外する。また、位置関係の計算には、ガウス・ニュートン法、レーベンバーグ・マーカート法等の非線形最小二乗法を利用できる。In this method, feature points are detected from the first ultrasonic image and the second ultrasonic image. Then, the feature points of the first ultrasonic image and the second ultrasonic image are matched to calculate homogeneous transformation matrices of the first ultrasonic image and the second ultrasonic image. Specifically, the second ultrasonic image is rotated clockwise by θ with respect to the first ultrasonic image, and is translated by t _x in the x-axis direction and t _y in the y-axis direction. When the feature points of the second ultrasonic image and the second ultrasonic image match, the homogeneous transformation matrix R for moving the coordinate system of the second ultrasonic image to match the first ultrasonic image is

becomes. That is, when the feature point (x, y) on the first ultrasound image moves to the feature point (x', y') on the second ultrasound image,

relationship is established. Note that the coordinates of the feature points contain errors, and the determined correspondence relationships themselves contain errors due to the influence of noise, so outliers that adversely affect the calculation are excluded by the RANSAC algorithm. Also, non-linear least-squares methods such as the Gauss-Newton method and the Levenberg-Marquardt method can be used to calculate the positional relationship.

Calculation of the homogeneous transformation matrix R is sequentially performed for two adjacent ultrasound images in the generation order, and is performed up to the (n−1)th ultrasound image and the nth ultrasound image. Let Rk be a homogeneous transformation matrix from the _k +1 (1≦k≦n−1)-th ultrasonic image to the k-th ultrasonic image. The following transform matrices are R ₁ R ₂ . . . R _k . The coordinate system of the first ultrasonic image is called the world coordinate system, and the coordinates of all ultrasonic images can be calculated by calculating homogeneous transformation matrices to the world coordinate system for all ultrasonic images. A single composite image is then generated by blending the pixels of all the ultrasound images.

In the present embodiment, it is assumed that first, a composite image including the cross section of the abdomen shown in FIG. 20 is generated.

The direction adjustment unit 353 has a function of adjusting the angle of the synthesized image and orienting the specific part included in the synthesized image in a predetermined direction. In the present embodiment, the orientation adjustment unit 353 adjusts the orientation of the composite image shown in FIG. 20 so that the navel is upward, for example. A specific method of adjustment will be described later.

The composite image whose direction has been adjusted by the direction adjustment section 353 is input to the display interface section 36 . The display interface unit 36 displays the synthesized image on the display 31 by developing the synthesized image data in the VRAM. Note that the display interface unit 36 may temporarily display the synthesized image on the display 31 before performing the direction adjustment described below, or may display the synthesized image on the display 31 after performing the direction adjustment.

(direction adjustment)
Hereinafter, one form in which the direction adjusting unit 353 adjusts the direction of the synthesized image will be specifically described. In the present embodiment, as indicated by the dashed line in FIG. 3, the orientation of the synthesized image is adjusted so that the umbilical region faces upward, utilizing the fact that the cross-sectional shape of the rectus abdominis muscle is generally bilaterally symmetrical.

As shown in FIG. 4, the direction adjustment section 353 includes an area setting section 353a, a symmetry evaluation section 353b, an area selection section 353c, and an angle calculation section 353d.

The region setting unit 353a is a functional block that sets one or a plurality of regions r having a line-symmetrical shape with respect to the central axis at arbitrary positions and at arbitrary angles. In the present embodiment, the shape of the region r is a rectangle that is symmetrical with respect to the central axis Ax, as indicated by the white line frame in FIG. When the region r equally includes the right and left rectus abdominis muscles, the central axis Ax of the region r can be regarded as the central axis passing through the navel of the abdomen. The region setting unit 353a sets the region r to be movable in order to search for the region r with high left-right symmetry.

More specifically, the region setting unit 353a selects one ultrasonic image from the plurality of ultrasonic images used to generate the composite image, and sets the transmission direction of the ultrasonic waves at the position on the surface of the subject 9. The area r is set by aligning the center axis Ax of the area r with the indicated axis. That is, the region setting unit 353a sets each region r by aligning the central axis Ax of each region r with each axis indicating the transmission direction of the ultrasonic wave at a plurality of mutually different positions on the surface of the subject 9. . The transmission direction of ultrasonic waves in each ultrasonic image can be identified based on a homogeneous transformation matrix to the coordinate system (world coordinate system) of the first ultrasonic image. Also, the trajectory of the probe 2 at the time of ultrasonic image acquisition corresponds to the upper side of each ultrasonic image. Therefore, as shown in FIG. 6, the trajectory of the probe 2 and information on the transmission direction of the ultrasonic waves are included in the synthesized image.

The region setting unit 353a may sequentially select from the first ultrasonic image to the n-th (n is a positive integer) ultrasonic image. A center axis of a substantially central ultrasonic image corresponding to the substantially center, and the center axes of a predetermined number of generated order ultrasonic images before and after the substantially central ultrasonic image are selected in sequence. When n is an even number, the substantially central ultrasound image corresponds to the n/2th ultrasound image. If n is an odd number, the approximately central ultrasound image corresponds to either the (n−1)/2th or (n+1)/2th ultrasound image. Also, let Dc be the axis indicating the transmission direction of the ultrasonic waves in the substantially central ultrasonic image. The region setting unit 353a first selects a substantially central ultrasonic image from the n ultrasonic images, and aligns the axis Dc of the substantially central ultrasonic image with the central axis Ax of the region r indicated by the dashed-dotted line in FIG. to set the region r. That is, the search start area is defined as an area r in which the transmission direction of the ultrasonic waves in the substantially central ultrasonic image coincides with the central axis. In the following description, when the transmission direction of ultrasonic waves in an ultrasonic image and the center axis of the area match, the ultrasonic image corresponds to the area.

After that, when the region r is to be moved, the region setting unit 353a selects another ultrasonic image, and moves again so that the transmission direction of the ultrasonic waves in the selected ultrasonic image matches the central axis Ax of the region r. , set the region r. In this embodiment, after selecting the substantially central ultrasonic image, the region setting unit 353a selects a predetermined number m of ultrasonic images before and after the substantially central ultrasonic image in the order of generation (if m is an even number, (n/2 )-(m/2) to (n/2)+(m/2)-1), the region r is moved.

Here, when the subject acquires an ultrasound image of the abdomen, the probe 2 is usually moved from the vicinity of one flank to the vicinity of the other flank via the umbilical region. Therefore, there is a high possibility that the position of the probe 2 is near the umbilicus when acquiring the substantially central ultrasound image. Therefore, it is not necessary to search for a highly symmetrical region r for regions corresponding to all ultrasound images, and m<n can be satisfied. As a result, the number of times the area r is moved can be suppressed, and the amount of calculation can be reduced.

The symmetry evaluation unit 353b shown in FIG. 4 is a functional block that evaluates the symmetry of the images on the left and right sides of the region r with respect to the central axis Ax of the region r. For example, when the region r shown in FIG. 5 is set, the symmetry evaluation unit 353b evaluates the degree of symmetry of the region r by calculating the correlation value between the left region and the right region with respect to the central axis Ax. do. As a method for calculating the correlation value, for example, Sum of Absolute Difference (SAD), Sum of Squared Difference (SSD), Normalized Cross-Correlation (NCC), Zero-means Normalized Cross-Correlation (ZNCC), etc. can be used. However, ZNCCs that are robust to changes in brightness are particularly preferred. For correlation values, see http://isl.sist.chukyo-u.ac.jp/Archives/tm.html, for example.

In addition, in the composite image, a linear pattern is formed because the boundary between muscles such as the rectus abdominis muscle and other tissues has high brightness. It is preferable that the degree-of-symmetry evaluation unit 353b calculates the correlation value particularly for the pattern in the region r.

The degree of symmetry may be evaluated using mutual information instead of the correlation value. See, for example, https://lp-tech.net/articles/9pF3Z for mutual information.

The degree-of-symmetry evaluation unit 353b evaluates the degrees of symmetry for all the regions r set by the region setting unit 353a, and records the degrees of symmetry in the memory each time the region r moves. FIG. 7 is a graph showing an example of the relationship between the ultrasound image number (image No.) corresponding to the region and the correlation value.

The region selection unit 353c is a functional block that selects the region r based on the degree of symmetry. In the present embodiment, the region selection unit 353c selects a region r having the highest degree of symmetry (region corresponding to the p-th ultrasonic image in the example shown in FIG. 7) from among the regions r evaluated for the degree of symmetry. to select. As a result, as shown in FIG. 8, a region r is selected in which the central axis Ax is located substantially in the middle of the left and right rectus abdominis muscles.

Note that the area selected by the area selection unit 353c does not necessarily have to be the area having the maximum degree of symmetry, and may be any area having a degree of symmetry equal to or greater than a predetermined threshold. A region with a relatively high degree of symmetry may be selected, for example the region with the second highest degree of symmetry.

The angle calculator 353d is a functional block that calculates the angle difference between a predetermined axis passing through the composite image and the central axis Ax of the selected region r. Adjust the angle of the composite image based on In this embodiment, the predetermined axis passing through the composite image is the symmetrical axis of the composite image. As a result, the composite image is rotated such that the central axis Ax shown in FIG. 8 is oriented upward. The data of the synthesized image adjusted by the direction adjustment unit 353 is output to the display interface unit 36, and the synthesized image with the navel directed upward is displayed on the display 31 as shown in FIG. This allows the subject to easily grasp the condition of the abdomen. Although only part of the composite image is displayed in FIG. 9, it goes without saying that the entire composite image may be displayed.

The shape of the region r is not particularly limited as long as it is linearly symmetrical with respect to the central axis. Also, the size of the region r is not particularly limited, but since the left and right rectus abdominis muscles have generally symmetrical shapes, it is preferable to make the width of the region r different from the width of each rectus abdominis muscle.

Also, when the subject brings the probe 2 into contact with the subject 9 , the transmission direction of ultrasonic waves is not always perpendicular to the surface of the subject 9 . In particular, when the transmission direction of the ultrasonic waves when the probe 2 passes near the navel is not perpendicular to the surface of the subject 9, the region set near the navel is aligned with the rectus abdominis. Tilt and degree of symmetry may not be high.

Therefore, as shown in FIG. 10, the region setting unit 353a is configured so that the angle θ between the axis D indicating the transmission direction of the ultrasonic waves in the selected ultrasonic image and the central axis Ax of the region r is equal to or less than a predetermined value. A region r may be set. Although the predetermined value is not particularly limited, it is set to the assumed maximum value (for example, ±5°) of the angle between the transmission direction of the ultrasonic waves and the normal to the surface of the subject 9 in the normal movement of the probe 2 . In this case, the region setting unit 353a selects one ultrasonic image, sets the region r, and then moves the region r by changing the angle θ by 1°, for example. The symmetry evaluation unit 353b evaluates the symmetry of the region r each time the angle θ changes, and the region selection unit 353c selects the region r with the highest symmetry. Accordingly, even if the transmission direction of ultrasonic waves is not perpendicular to the surface of the subject 9, the region r set near the navel has the highest degree of symmetry at any angle, so an appropriate region is selected. can do.

(Processing procedure)
FIG. 11 is a flow chart showing the processing procedure of the ultrasonic imaging method according to this embodiment.

In step S<b>1 , the probe 2 transmits ultrasonic waves toward the interior of the subject 9 from a plurality of mutually different positions on the surface of the subject 9 . As a result, the probe 2 receives the ultrasonic waves reflected inside the subject 9 and outputs an echo signal from the probe 2 .

In step S<b>2 , the ultrasonic image generator 351 generates ultrasonic images corresponding to a plurality of different positions on the surface of the subject 9 . In this embodiment, each time an echo signal is output from the probe 2, the ultrasonic image generator 351 generates an ultrasonic image. Steps S1 and S2 are repeated until scanning of the probe 2 is completed (Yes in step S3).

When the scanning of the probe 2 is finished, in step S4 (image synthesizing step), the image synthesizing unit 352 synthesizes the ultrasonic images at the respective positions to generate a synthetic image of the cross section of the subject 9 .

Subsequently, in step S5 (direction adjustment step), the direction adjustment unit 353 orients the specific part included in the synthesized image in a predetermined direction. The adjustment by the direction adjustment unit 353 may be performed automatically after the synthetic image is generated, or may be performed when a predetermined operation via the input device 32 or the like is received. A more detailed processing procedure of step S5 will be described later.

Thereafter, in step S<b>6 (display step), the synthesized image whose orientation has been adjusted is displayed on the display 31 .

FIG. 12 is a flow chart showing the detailed processing procedure of step S5 in this embodiment. Step S5 has steps S5-1 to S5-7.

First, in step S5-1, the region setting unit 353a selects one ultrasonic image from a plurality of ultrasonic images used to generate the composite image. In this embodiment, for example, an approximately central ultrasound image corresponding to the center of the generation order of the ultrasound images is selected.

Subsequently, in step S5-2, the region setting unit 353a aligns the center axis Ax of the region r with the axis indicating the transmission direction of the ultrasonic waves in the selected ultrasonic image, and sets the region r in the synthesized image.

Subsequently, in step S5-3, the degree-of-symmetry evaluation unit 353b evaluates the degree of symmetry of the set region r.

If the degree of symmetry has not been evaluated for all regions to be searched (No in step S5-4), the process proceeds to step S5-5, and the region setting unit 353a selects other ultrasonic waves that have not been selected so far. Select an image. Then, steps S5-2 and S5-3 are performed for the selected other ultrasound image. Steps S5-2, S5-3 and S5-5 are repeated until the degree of symmetry is evaluated for all regions to be searched (Yes in step S5-4).

After that, in step S5-6, the region selection unit 353c selects the region r having the maximum degree of symmetry, for example. Note that the region selection unit 353c may select a region r with a relatively high degree of symmetry, such as a region with the second highest degree of left-right symmetry.

Subsequently, in step S5-7, the angle calculation unit 353d calculates the angle difference between the left-right symmetry axis of the synthesized image and the central axis Ax of the region r selected by the region selection unit 353c, and the direction adjustment unit 353 The synthesized image is rotated by adjusting the angle of the synthesized image based on the angle difference.

(Summary)
As described above, in the present embodiment, the orientation of the synthesized image is adjusted so that the umbilical region is directed upward, utilizing the fact that the cross-sectional shape of the rectus abdominis muscle is generally bilaterally symmetrical. As a result, the subject or the like can be displayed with a synthesized image that facilitates understanding of the state of the abdomen.

It should be noted that the technique of the present embodiment can be applied to regions other than the rectus abdominis muscle as long as the region includes approximately bilaterally symmetrical tissues. Such sites include the back, waist, neck, and the like.

[Embodiment 2]
In the second embodiment, a configuration will be described in which the orientation of the composite image is adjusted by comparing the composite image with the template image while rotating the composite image. FIG. 13 is a block diagram showing the configuration of an ultrasonic imaging apparatus 3' according to the second embodiment. The ultrasonic imaging apparatus 3' has a configuration in which the direction adjusting section 353 in the ultrasonic imaging apparatus 3 shown in FIG. 2 is replaced with a direction adjusting section 353'. A template image T is stored in the auxiliary storage device 33 .

FIG. 14 is a block diagram showing functions and the like of the direction adjusting section 353'. The direction adjustment unit 353' includes a virtual rotation unit 353e, a correlation evaluation unit 353f, an angle determination unit 353g, and a rotation unit 353h.

The virtual rotation unit 353 e is a functional block that virtually rotates at least one of the template image T of the synthesized ultrasound image and the synthesized image generated by the image synthesizing unit 352 . The template image T in the present embodiment is an ultrasonic composite image showing an abdominal cross-section including the umbilical region (specific part) and oriented upward (predetermined direction). A template image T can be created by averaging multiple individual abdominal ultrasound composite images. Alternatively, if an ultrasound composite image of the same subject has been generated in the past, the past composite image of the subject whose direction has been adjusted may be used as the template image T. FIG. In the present embodiment, it is assumed that the synthetic image whose direction has been adjusted is the template image T, and the synthetic image F shown in FIG. 15 is newly generated.

The virtual rotation unit 353e may rotate the template image T, but rotates only the synthetic image F in this embodiment. The virtual rotation unit 353e may rotate the synthetic image F by 360°. is a substantially circular arc slanted to the right, the composite image F is rotated counterclockwise within a range of, for example, 45°. The outer shape of the cross section in the composite image F is, for example, the left end corresponding to the contact position at the start of scanning of the probe 2, the right end corresponding to the contact position at the end of scanning, and the start and end of scanning. It can be determined from the coordinates of each portion of the central portion corresponding to the contact position at the middle time point.

Also, the angle by which the virtual rotation unit 353e rotates the composite image F at one time is not particularly limited, but in the present embodiment, the composite image F is rotated by a predetermined angle, for example, by 1°. An example of the rotated synthetic image F is shown in FIG.

The correlation evaluation unit 353f is a functional block that evaluates the correlation between the template image T and the synthesized image. Specifically, each time the virtual rotation unit 353e rotates the synthesized image F, the correlation degree evaluation unit 353f virtually moves the rotated synthesized image F and rotates the synthesized image F, as shown in FIG. The template image T is matched, and the relative position where the correlation value between the composite image F and the template image T is maximized is specified. Then, the correlation degree evaluation unit 353f records the correlation value at the specified relative position in the memory for each rotation angle from the initial position of the synthesized image F as the correlation degree.

Note that the same method as in the first embodiment can be used for calculating the correlation value, and mutual information may be used instead of the correlation value. Further, the rotation of the synthetic image F by the virtual rotation unit 353e and the matching of the synthetic image F and the template image T by the correlation evaluation unit 353f are virtual and do not have to be displayed on the display 31. FIG. Further, when the virtual rotation unit 353e rotates the synthetic image F once, the correlation degree evaluation unit 353f may terminate the correlation degree evaluation process if the correlation degree is equal to or greater than a predetermined threshold value.

An angle determination unit 353g illustrated in FIG. 14 is a functional block that determines the rotation angle of the synthetic image F based on the degree of correlation evaluated by the degree-of-correlation evaluation unit 353f. The rotation angle here means the angle by which the composite image F is actually rotated by the rotation unit 353h described later. In the present embodiment, a synthetic image Fmax having the highest degree of correlation is selected from the synthetic images F whose correlation degrees have been evaluated, and the angle of the synthetic image Fmax with respect to the initial position is determined as the rotation angle of the synthetic image F.

Note that the synthesized image selected by the correlation evaluation unit 353f does not necessarily have to be the synthesized image with the highest correlation, and may be any synthesized image with a correlation value equal to or greater than a predetermined threshold. For example, a synthetic image with a relatively high degree of correlation, such as a synthetic image with the second highest degree of correlation, may be selected.

The rotation unit 353h is a functional block that rotates the composite image F according to the rotation angle determined by the angle determination unit 353g. Since the synthetic image F rotated by the rotating unit 353h is the synthetic image evaluated to have the highest degree of correlation with the template image T, it is adjusted so that the navel is substantially upward. The rotating unit 353h outputs data of the rotated synthesized image to the display interface unit 36, and in response, the display interface unit 36 displays the synthesized image in which the navel is directed in a desired direction (for example, upward). 31.

(Processing procedure)
FIG. 18 is a flowchart showing the processing procedure of the ultrasonic imaging method according to this embodiment. In the flowchart shown in FIG. 18, the overall processing procedure is the same as the flowchart shown in FIG. 11, but step S5 for adjusting the orientation of the synthesized image is replaced with step S5'.

FIG. 19 is a flow chart showing the detailed processing procedure of step S5' in this embodiment. Step S5' has steps S5-8 to S5-12.

First, in step S5-8, the virtual rotation unit 353e shown in FIG. 14 rotates the composite image F by 1°, for example.

Subsequently, in step S5-9, the correlation evaluation unit 353f evaluates the correlation between the template image T and the synthesized image F while virtually moving the rotated synthesized image F. FIG.

If the rotation angle of the synthesized image F from the initial position has not reached a predetermined value (for example, 45°) (No in step S5-10), the process returns to step S5-8. Then, steps S5-8 and S5-9 are repeated until the rotation angle of synthesized image F from the initial position reaches a predetermined value (Yes in step S5-10).

After that, in step S5-11, the angle determining unit 353g determines the rotation angle from the initial position of the synthesized image Fmax having the highest degree of correlation among the synthesized images F evaluated for the degrees of correlation, and determines the rotation angle of the synthesized image F Determined as

Subsequently, in step S5-12, the rotation section 353h rotates the composite image F according to the rotation angle determined by the angle determination section 353g.

(Summary)
As described above, in the present embodiment, the orientation of the synthesized image is adjusted by rotating the synthesized image and comparing it with the template image. Unlike the first embodiment, which utilizes bilateral symmetry of living tissue, in this embodiment, it is possible to adjust the orientation of a composite image of any part that does not include bilaterally symmetrical tissue.

(Additional notes)
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims, and forms obtained by appropriately combining the technical means disclosed in each embodiment are also within the scope of the present invention. Included in the technical scope.

In the above embodiment, the case where the orientation of the synthesized image of the cross section of the abdomen is adjusted so that the umbilical region faces upward has been described, but the orientation of the synthesized image can be changed as appropriate. For example, the orientation of the composite image may be adjusted so that the umbilical region faces downward or laterally.

Further, in the above embodiment, the orientation of the composite image is adjusted by utilizing the left-right symmetry of the living tissue or by comparing the composite image with the template image. , but not limited to. For example, in the case of a composite image of a cross section of the abdomen, the umbilical region can be adjusted upward by equalizing the heights of the left and right ends corresponding to the contact positions at the start and end of scanning of the probe 2. may

Further, in the above embodiment, in order to obtain ultrasonic images corresponding to a plurality of mutually different positions on the surface of the subject 9, the probe 2 is moved along the surface of the subject 9, and ultrasonic waves are emitted from the probe 2. was intermittently transmitted, the mode of obtaining an ultrasonic image is not limited to this. For example, a plurality of ultrasonic transmission/reception devices may be arranged in the subject 9, and ultrasonic waves may be transmitted simultaneously from each ultrasonic transmission/reception device.

INDUSTRIAL APPLICABILITY The present invention can be applied to both medical and non-medical applications, and is particularly suitable for applications in which subjects who are not medical professionals check their own health conditions on a daily basis.

1 Ultrasonic Imaging System 2 Probe 3 Ultrasonic Imaging Device 31 Display 32 Input Device 33 Auxiliary Storage Device 34 Communication Interface Section 35 Signal Processing Section 351 Ultrasonic Image Generation Section 352 Image Synthesis Section 353 Direction Adjustment Section 353' Direction Adjustment Section 353a Area Setting unit 353b Symmetry evaluation unit 353c Region selection unit 353d Angle calculation unit 353e Virtual rotation unit 353f Correlation evaluation unit 353g Angle determination unit 353h Rotation unit 36 Display interface unit 9 Subject Ax Central axis D Axis Dc indicating transmission direction Transmission direction Axis F Synthetic image Fmax Synthetic image P Ultrasonic imaging program r Region T Template image Tc Substantially central ultrasonic image

the term

Not necessarily all objectives or advantages can be achieved in accordance with any particular embodiment described herein. Thus, for example, it will be appreciated by those skilled in the art that a particular embodiment may be as taught herein without necessarily achieving other objectives or advantages as taught or suggested herein. may be configured to operate to achieve or optimize one or more effects/benefits.

All processes described herein can be embodied and fully automated by software code modules executed by a computing system including one or more computers or processors. Code modules may be stored in any type of non-transitory computer readable medium or other computer storage device. Some or all methods may be embodied in dedicated computer hardware.

It will be apparent from this disclosure that there are many other variations besides those described herein. For example, depending on the embodiment, specific acts, events, or functions of any of the algorithms described herein may be performed in different sequences, added, merged, or omitted entirely. (eg, not all acts or events described are required for execution of the algorithm). Moreover, in certain embodiments, operations or events may be performed in parallel rather than serially, e.g., across multithreaded processing, interrupt processing, or multiple processors or processor cores, or on other parallel architectures. can be done. Moreover, different tasks or processes may be performed by different machines and/or computing systems that may work together.

Various example logical blocks and modules described in connection with the embodiments disclosed herein can be implemented or executed by a machine such as a processor. The processor may be a microprocessor, but in the alternative, the processor may be a controller, microcontroller, or state machine, or combinations thereof, or the like. A processor may include electrical circuitry configured to process computer-executable instructions. In another embodiment, the processor includes an application specific integrated circuit (ASIC), field programmable gate array (FPGA), or other programmable device that performs logical operations without processing computer-executable instructions. A processor may also be a combination of computing devices, such as a combination of a digital signal processor (digital signal processor) and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other It can be implemented as a configuration like Although described herein primarily in terms of digital technology, the processor may also include primarily analog components. For example, some or all of the signal processing algorithms described herein may be implemented with analog circuitry or mixed analog and digital circuitry. A computing environment includes any type of computer system including, but not limited to, a computer system based on a microprocessor, mainframe computer, digital signal processor, portable computing device, device controller, or computational engine within the apparatus. be able to.

Unless otherwise specified, conditional language such as "could," "could," "would," or "could," implies that although a particular embodiment includes certain features, elements and/or steps, other Embodiments are to be understood in a sense within the context commonly used to convey that they do not include. Thus, such conditional language generally states that any method in which features, elements and/or steps are required in one or more embodiments or that one or more embodiments impose these features. , elements and/or steps are not necessarily meant to include logic to determine whether they are included or performed in any particular embodiment.

Disjunctive language such as the phrase "at least one of X, Y and Z" means that items, terms, etc. are any of X, Y, Z, or any combination thereof, unless otherwise stated. (e.g. X, Y, Z). Thus, such disjunctive languages generally require each of at least one of X, at least one of Y, or at least one of Z, for each specific embodiment to be present. does not mean

Any process description, element or block in the flow diagrams described herein and/or illustrated in the accompanying drawings represents one or more executable instructions for implementing a particular logical function or element in the process. to potentially represent a module, segment, or portion of code, including Alternate embodiments are included within the scope of the embodiments described herein, where an element or function can be substantially modified, depending on the functionality involved, as understood by one skilled in the art. may be performed simultaneously or in reverse order, removed from those shown or described, and out of order.

Unless otherwise specified, numbers such as "a" should generally be construed to include one or more of the item being described. Thus, phrases such as "a device configured to" are intended to include one or more of the listed devices. One or more such listed devices may also be collectively configured to carry out the recited references. For example, "a processor configured to run A, B and C below" means a first processor configured to run A and a second processor configured to run B and C. and a processor of In addition, even if a specific number of recitations of the introduced examples is explicitly recited, one skilled in the art will appreciate that such recitations are typically at least the number recited (e.g., other modifiers A mere recitation of "two recitations" without using should be taken to mean generally at least two recitations, or more than two recitations.

In general, terms used herein should generally be interpreted as "non-limiting" terms (e.g., the term "comprising" should be interpreted as "including at least as well as", "including The term "having" shall be construed as "having at least" and the term "including" shall be construed as "including but not limited to", etc.). will be determined by those skilled in the art.

For purposes of description, the term "horizontal" as used herein, regardless of its orientation, refers to a plane parallel to the plane or surface of the floor of the area in which the system described is used, or defined as the plane in which the method is performed. The term "floor" can be replaced with the terms "ground" or "water surface". The term "vertical/plumb" refers to the direction perpendicular/perpendicular to the defined horizontal line. Terms such as "above", "below", "below", "above", "side", "higher", "lower", "above", "over", "below", etc. are defined relative to the horizontal plane. ing.

The terms “attach,” “connect,” “pair,” and other related terms used herein, unless otherwise noted, include removable, movable, fixed, adjustable, and/or should be construed to include a removable connection or coupling. A connection/coupling includes a direct connection and/or a connection with an intermediate structure between two components described.

As used herein, unless otherwise specified, numbers preceded by terms such as "approximately," "about," and "substantially" include the recited number and also It represents an amount approximating the stated amount that will perform a desired function or achieve a desired result. For example, "about," "about," and "substantially" refer to less than 10% of the stated numerical value, unless otherwise specified. As used herein, terms such as "approximately," "about," and "substantially" predisclose features of the embodiments that also perform the desired function. or represents a feature with some variability to achieve the desired result for that feature.

Many variations and modifications may be made to the embodiments described above, and these elements are to be understood as being among other permissible examples. All such modifications and variations are intended to be included within the scope of this disclosure and protected by the following claims.

Claims (13)

An ultrasonic wave that receives ultrasonic waves that are transmitted toward the interior of the subject from a plurality of positions different from each other on the surface of the subject and that are reflected inside the subject, thereby generating ultrasound images corresponding to the respective positions. an image generator;
an image synthesizing unit that synthesizes the ultrasonic images at the respective positions to generate a synthetic image of the cross section of the subject;
A direction adjustment unit that adjusts the angle of the synthesized image and orients a specific part included in the synthesized image in a predetermined direction ,
The direction adjustment unit
A region setting unit that sets one or a plurality of regions having a line-symmetrical shape with respect to the central axis at arbitrary positions and at arbitrary angles in the synthesized image;
a symmetry evaluation unit that evaluates the degree of symmetry of images on the left and right sides of the region with respect to the central axis;
a region selection unit that selects the region based on the degree of symmetry;
an angle calculation unit that calculates an angle difference between a predetermined axis passing through the synthesized image and the central axis of the selected region;
adjusting the angle of the composite image based on the angle difference;
Ultrasound imaging device. The specific part includes the umbilical region of the abdomen,
2. The ultrasonic imaging apparatus according to claim 1, wherein said direction adjusting unit aligns said umbilicus with a desired direction of said screen display when said composite image is displayed on said screen. 3. The ultrasonic imaging apparatus according to claim 1 , wherein the region setting unit sets the region by aligning a central axis of the region with an axis indicating the transmission direction of the ultrasonic wave at the position. 4. The area setting unit according to any one of claims 1 to 3, wherein the area setting unit sets each area by aligning the central axis of each area with each axis indicating the transmission direction of the ultrasonic waves at the plurality of positions. of ultrasound imaging equipment. The area setting unit sets the area so as to be movable to the synthesized image,
5. The ultrasonic imaging apparatus according to claim 1 , wherein said symmetry evaluation unit evaluates said symmetry each time said region moves. 6. The ultrasonic imaging apparatus according to claim 5 , wherein said region selection unit selects one of said regions having a degree of symmetry equal to or greater than a predetermined threshold among said degrees of symmetry. 7. The ultrasonic imaging apparatus according to claim 5 , wherein said region selection unit selects said region having the highest degree of symmetry among said degrees of symmetry. The ultrasonic imaging apparatus according to claim 1 , wherein the region setting unit selects, from among the plurality of ultrasonic images, a substantially central ultrasonic image corresponding to substantially the center in order of generation. The region setting unit includes, among the plurality of ultrasonic images, a central axis of a substantially central ultrasonic image corresponding to substantially the center in order of generation, and a predetermined number of generation orders before and after the substantially central ultrasonic image. 2. The ultrasonic imaging apparatus according to claim 1 , wherein the central axes of the ultrasonic images are sequentially selected, and the central axis of the region is aligned with the selected central axis to set the region. 10. The ultrasonic imaging apparatus according to any one of claims 1 to 9 , further comprising a display section for displaying said composite image on a display. a probe that transmits ultrasonic waves toward the inside of the subject from a plurality of positions different from each other on the surface of the subject and receives the ultrasonic waves reflected inside the subject;
An ultrasound imaging system comprising an ultrasound imaging device according to any one of claims 1 to 10 . An ultrasonic wave that receives ultrasonic waves that are transmitted toward the interior of the subject from a plurality of positions different from each other on the surface of the subject and that are reflected inside the subject, thereby generating ultrasound images corresponding to the respective positions. an image generating step;
an image synthesizing step of synthesizing the ultrasonic images at each position to generate a synthetic image of the cross section of the subject;
A direction adjustment step of adjusting the angle of the synthesized image and orienting a specific part included in the synthesized image in a predetermined direction ;
The direction adjustment step includes:
A region setting step of setting one or a plurality of regions having a line-symmetrical shape with respect to the central axis in the synthesized image at arbitrary positions and at arbitrary angles;
a symmetry evaluation step of evaluating the symmetry of the images on the left and right sides of the region with respect to the central axis;
a region selection step of selecting the region based on the degree of symmetry;
an angle calculation step of calculating an angle difference between a predetermined axis passing through the synthesized image and the central axis of the selected region;
adjusting the angle of the composite image based on the angle difference;
Ultrasound imaging method. receiving ultrasonic waves transmitted toward the interior of the subject from a plurality of positions different from each other on the surface of the subject and reflected inside the subject, and generating ultrasound images corresponding to the respective positions;
synthesizing the ultrasound images at each of the positions to generate a synthetic image of the cross section of the subject; and
Adjusting the angle of the synthesized image, orienting a specific part included in the synthesized image in a predetermined direction ,
The angle adjustment is
In the synthesized image, one or more areas having a line-symmetrical shape with respect to the central axis are set at arbitrary positions and at arbitrary angles,
Evaluating the degree of symmetry of the images on the left and right sides of the region with respect to the central axis,
selecting the region based on the degree of symmetry;
calculating an angular difference between a predetermined axis passing through the composite image and the central axis of the selected region;
adjusting the angle of the composite image based on the angle difference;
An ultrasound imaging program that causes a computer to perform operations .

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